Tumor Lysis Syndrome As a Major Risk Factor of Posterior Reversible Encephalopathy Syndrome in Patients with Lymphoid Malignancies of Childhood

Posterior reversible encephalopathy syndrome (PRES) is a neurological complication that is caused by various factors such as hypertension, the use of calcineurin inhibitor(cyclosporin or tacrolimus). Its initial symptoms usually are seizure, headache, visual disorder. Although PRES associated with lymphoid malignancies has been reported, it only consits of case reports or small series. Furthermore, its risk factors have never been well-documented.

A total of 126 pediatric patients with lymphoid malignancies received chemotherapy in our hospital between January 2000 and October 2010. Of these patients 84 were boys and 42 were girls. Age of patients at the onset of their respective diseases was 4 months to 15 years(median: 5y). One hundred and eight patients had acute lymphoblastic leukemia, 15 were Non-Hodgkin lymphoma and 2 were Hodgkin lymphoma.

Of 126 patients, 6 developed PRES. The initial symptoms were seizure, cortical blindness and upper limb paralysis. All the patients had hypertension before developing PRES. In addition, 3 patients had tumor lysis syndrome(TLS). The median time from the initiation of treatment was 10.5 days (range: 6–35 days), Two patients developed epilepsy as a sequela. On statistical analysis, the only risk factors for PRES was the development of TLS.

Although various factors were reported, TLS-related PRES has never been described. Some patients developed PRES in the early period of induction treatment while the others in the late period. The difference between them remains to be seen. However, TLS may cause renal dysfunction in combination with hypertension induced by chemotherapeutic drugs such as prednisolone. Renal dysfunction and following hypertension might have induced PRES. We must pay attention to the state especially of the patients who developed TLS in the course of chemotherapy.

No relevant conflicts of interest to declare.